The only highly accurate way to determine the number of calories burned during an elliptical workout is to use indirect calorimetry equipment that tracks your breathing rate as you exercise. This equipment is typically found only at high-level athletic training facilities and doctor’s offices. Since you probably don’t have access to this equipment, the next-best option is to manually calculate the number of calories you burn. This method is not 100 percent accurate, but it will give you a better gauge of your calories burned than will the elliptical’s calorie tracking program.
Metabolic equivalents, or METs, can estimate the number of calories burned during a high-intensity elliptical workout. One MET is equal to your energy expended during rest. A high-intensity elliptical workout is about six METs or higher.
Calculate the number of calories burned by multiplying METs by bodyweight in kilograms by exercise time in hours. Divide your weight in pounds by 2.2 to convert to kilograms. As an example, a 180-pound person exercising on the elliptical at a high intensity for 30 minutes would burn 6 x 81.8 x 0.5 equals about 246 calories.
Exercise to the Beat (heartbeat, that is)
There is a strong correlation between heart rate and energy expenditure. L.R. Keytel, et al., developed a formula for men and women that estimates the number of calories burned based on your weight, age and duration of the workout. As your heart rate increases during a high-intensity elliptical workout, your breathing rate does as well.
This formula uses this information to estimate calories burned during a workout almost as well as calorimetry equipment:
Use kilograms for weight, years for age and hours for workout duration. For men: ((-55.0969 + (0.6309 x heart rate) + (0.1988 x weight) + (0.2017 x age))/4.184) x 60 x workout duration. For women: ((-20.4022 + (0.4472 x heart rate) – (0.1263 x weight) + (0.074 x age))/4.184) x 60 x workout duration
Consider the After-Burn
When you exercise at a high intensity, you elicit a beneficial after-burn effect called excess post-oxygen consumption (EPOC). In short, your body continues to burn calories at an elevated rate for up to 48 hours following vigorous exercise.
The problem is that it’s difficult to accurately determine EPOC because of factors like fitness level, gender, level of muscle mass, and other factors that play a role in how many calories your body burns after your elliptical workout is done.
Drs. Chantel Vella and Len Kravitz of the University of New Mexico compared different studies on excess post-oxygen consumption and found that the after-burn effect typically ranges from as little as 15 calories up to 150 or more calories your body burns as it recovers from the workout. The more intense your workout, the greater the EPOC benefit.
Factors to Consider
Whether you opt to manually calculate your calories burned or simply go by what your elliptical machine is telling you, it’s important to realize that there are many factors affecting its accuracy. If you have an above average amount of lean muscle mass, for example, your body naturally burns more calories than someone with a lower percentage of muscle.
Your age, fitness level, bodyweight, exercise technique, elliptical stride length and your genetic makeup all play a role in the number of calories you’ll burn during an elliptical workout. So, try not to focus too much on how many calories you’re burning, but rather, how many inches you’ve melted away from your waistline.
Bonus Tip for Impatient Folks (like me!)
The easiest way to estimate the number of calories burned during a vigorous elliptical workout is to use an online calorie-burn calculator. There are many out there and some are better than others. I prefer the one offered by Shapesense — find it here. It factors in several different factors, including your age, weight, average heart rate, and others. It seems to be one of the more accurate online calorie calculators I’ve come across. It even lets you find your net calories burned, not just the gross calories burned like other online calculators do. The result is a more accurate reading.
An online calculator that uses your average heart rate to determine your calorie burn is more accurate compared to the generic ones that only ask for your weight, height and exercise duration. Check your heart rate every five minutes, or so, as you workout and note the readings by writing them down, using a heart rate monitor, or by remembering each reading. Find your average heart rate at the end of your workout by adding them up and and dividing by the total number of readings (you remember how to find averages from grade school, right?!).
In general, your elliptical will over-estimate the number of calories burned by 25% or more. I suggest you completely ignore this information and rely on some of the other tips above to determine a more accurate estimate of the calories burned during your HIIT elliptical workout.
1. BuiltLean: 3 Reasons to Never Trust Estimated Calorie Burn on Cardio Machines
2. American Council on Exercise: Resting Metabolic Rate: Best Ways to Measure It — and Raise It, Too
3. Journal of Sports Sciences: Prediction of Energy Expenditure from Heart Rate Monitoring during Submaximal Exercise
4. University of New Mexico: Exercise After-Burn – Research Update
5. Compendium of Physical Activities: 2011 Compendium of Physical Activities Reference List